Remove the ramekins from the oven and cool.Refrigerate, covered, for at least 3 hours or overnight. Close to serving time, combine the sugars in a small bowl. Preheat a broiler and sprinkle 1 tablespoon of the mixed sugars evenly over the surface of each custard. Broil (as quickly as possible) until the sugar is caramelized. Alternately, you cancaramelize the sugar with a propane torch. Serve within 1 hour to maintain the crispness of the sugar topping.